Wicked Iron: The Celtics often struggle to execute close games.

When the Boston Celtics began to destroy the league in the final months of the regular season, their dominance hid what had been one of their biggest problems up to that point: the clutch offense.

On Jan. 22, the Celtics were 23-24, going 9-17 in games within five points in the final five minutes…and 14-7 otherwise. That’s when they turned things around with a 28-7 record in their last 35 games to move from 10th place to 2nd in the Eastern Conference.

The Celtics had both the league’s No. 1 offense and No. 1 defense in those 11 weeks, outscoring opponents by an incredible 15.5 points per 100 possessions.

But by beating their opponents so decisively (20 of 28 wins were in double digits, 15 were 20 or more points), the Celtics didn’t quite solve their clutch problems. They were just 4-5 in games that were under five in the last five over the past 11 weeks, scoring just 79 points on 90 offensive clutch possessions (87.8 for 100). Only the New York Knicks had a worse clutch offense during that span.

Thus, the Celtics finished the season 38-9 (.809, league-best) in non-clutch games and 13-22 (.371, second-worst) in clutch games. It was the third largest differential in this regard in the 26 years for which we have clutch data.

The Celtics (plus-7.4) were 1.9 points per 100 possessions better than the Golden State Warriors (plus-5.5) in the regular season, but the Western Conference champions have home-court advantage in this series as they won two more games. Fittingly, the Warriors won the tight regular season meeting between the two teams, while the Celtics won the blowout.

Things accelerated in the first round of the playoffs. The Celtics swept the Brooklyn Nets, but all four games were within five points in the final five minutes. And in those four games, Boston scored 25 points on 21 clutch possessions (119 for 100), with Jayson Tatum’s Game 1 buzzer-beater being the highlight.

Brooklyn, of course, had one of the worst defenses in the playoffs. Since that series, the Celtics’ playoff clutch offense has fallen below one point per possession (89.1 per 100 through Sunday). Late-game offensive struggles late in Games 6 and 7 of the Eastern Conference Finals nearly knocked them out of a 3-2 series lead and headed into the offseason with a ton of regrets.

Such regret remains a possibility, especially after Boston lost another fourth-quarter lead in Game 4 of the NBA Finals on Friday. After taking a five-point lead with 7½ minutes remaining, the Celtics scored just twice (six points) on their last 12 possessions, and they went scoreless on the six possessions labeled as a “clutch”. (because they entered the last five minutes with the score less than five).

It’s not like the Celtics are having an identity crisis. They know who they are and how they want to attack offensively, spacing the ground and setting weak defenders in action against Tatum and Jaylen Brown. But for some reason, they often struggled to execute close games.

Here’s how things turned out badly for the Celtics (and good for the Warriors) at the end of Game 4.

1. Defend the screen from flares

Flare screens (for multiple players) have become a big part of the Celtics offense in this series. At the start of the fourth quarter, Tatum got one open 3 when Andrew Wiggins got caught under a flare screen and Jordan Poole was late to go out.

With a chance to build on that five-point lead, midway through the fourth, Robert Williams III set up a flare screen for Tatum which flattened Andrew Wiggins. But Tatum didn’t have an open shot, as Kevon Looney was there, putting out Williams. Tatum drove the baseline, Poole provided timely assist and Klay Thompson passed to Derrick White, forcing Tatum to back up and reset:

Warriors defend the flare screen

Marcus Smart set a screen for Stephen Curry to defend Tatum, but Curry was able to stay in front of Tatum’s initial drive and force a hard pullback and timer violation:

Defense of Stephen Curry

It’s possible Tatum could have attacked quicker after the catch or gotten the ball back quicker when Poole came to help, but the jump pass to Brown in the far corner would have been tough against Looney.


2. The Thompson stops

Thompson struggled with his shot (10 for 33) in the first two games of the Finals. But he’s been better the past two, and he had 13 second-half points on Sunday, while making several big plays at the other end of the field.

Thompson cut that five-point deficit to three with a difficult turnaround in the painting. And he followed up with a formidable defensive game.

As Wiggins anticipated a loop from Tatum on a Smart crossscreen, Tatum clipped the gate, leaving his defender in the dust. But Thompson saw what was happening, put out Brown in the corner and challenged Tatum to the clear edge:

Klay Thompson's Defense

Two possessions later (No. 1 clutch possession for the Celtics), Brown rejected a screen, looking to beat Thompson from the dribble. But Thompson stuck with him and forced a tough runner who chickened out:

Klay Thompson's Defense

Later in the fourth (Clutch Possession #5), Thompson completely closed an isolation from Brown, keeping him in front and not giving him enough room for a back jumper. Brown fed the ball to Horford, but his 3-pointer was a little rushed with Looney shutting down:

Klay Thompson's Defense

With the Celtics down six (not a clutch possession), Horford made a corner 3 the next trip on the ground. And after a Looney layup (when the Celtics pulled the ball out of Curry’s hands), the Celtics had their sixth and final clutch possession of Game 4.

Again, Thompson was most responsible for the stoppage. Brown cut the door and Smart managed to sneak past, but Thompson stayed with him and (with help from Wiggins) forced a turnover:

Celtics turnover

There were more vulnerable defenders – Curry and (sometimes) Poole – on the floor when Thompson got those saves, and it looks like the Celtics picked the wrong guy to attack.


3. Help, recover and challenge

When Curry knocked an elbow runner to put the Warriors up three with just under four minutes to go, the Celtics called time out and put up a play (clutch possession #3) to bring Curry into action against Tatum.

But as he took a stint from Derrick White, Tatum stopped for a split second. Wiggins rounded White and Draymond Green pinched Brown to prevent a Tatum drive. Wiggins then assisted on a Brown drive and quickly recovered to challenge Tatum’s 3-pointer:

Andrew Wiggins assists and recovers

The next possession (possession of clutch n°4), it is Green who does the same thing. Thompson (one possession before the above iso) stayed ahead of an isolation from Brown, but Green helped with the paint. Brown was sent off to Smart and Green made a huge effort to contest the shot as best he could:

Drayond Green helps and recovers

Brown got the offensive rebound, but Wiggins stayed ahead of a spinning move from Tatum and Smart missed another 3 against another green contest.


4. Sometimes slow and stagnant

The Celtics’ clutch problems on Friday weren’t nearly as self-inflicted as their problems in Game 6 of the Conference Finals. As noted above, there were some good defensive plays/actions from all six Warriors (even Poole!) who played within the time limit.

But on their first clutch possession (Brown throwing off the screen and missing the runner), note that there were just 11 seconds left on the shot clock before the Celtics ran anything designed to gain an advantage, for they were so slow to enter into their attack. :

Celtics slow build-up

Curry was amazing in Game 4, but the difference in those games was almost entirely on the Boston offense, which scored 125.5 points per 100 possessions in its two wins and just 95.4 in its two losses. Turnovers and rebounds are part of it, but shooting is the most important aspect of this game.

Interestingly, the Celtics shot only slightly more effectively in the first 12 seconds of the shot clock in their wins (effective field goal percentage of 66.9%) than in their losses (63.7%). The biggest difference in their shooting was in the last 12 seconds of the shot clock: 54.1% win, 35.7% loss.

Late execution is important, and it is also important to avoid these late situations. The Celtics also had several possessions earlier in Game 4 where they just weren’t very determined and colonized for bad shots.


5. More clutch time coming?

In four games, the Warriors edged the Celtics by just one point. It’s now a three-game streak and there’s a good chance at least one more game will end in the streak.

Surprisingly, the Celtics are two wins away from a championship that has yet to truly resolve their late-game offensive issues. Of course, the Milwaukee Bucks had similar issues last season, then went 3-0 in games within five of the last five, scoring 25 points on 17 clutch possessions (147 for 100), in the Finals. And that was against the team – Phoenix – which is otherwise 65-23 (.739) in clutch games over the past two years.

Even more so than this series, it feels like anything can happen in the next seven days. Game 5 is Monday (9 p.m. ET, ABC) in San Francisco.

John Schuhmann is a senior statistics analyst for NBA.com. You can email him here, find his archive here and follow him on Twitter.

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